Let say you made your own claymation animations. If people go to your own site, they get no ads, and can choose to buy merch from you if they like. However, a common issue for a creator like that would be content thieves with an ad plan. They’d reupload to YouTube, claim it as their own, monetize ads, and maybe the people who see the first animations there don’t even hear about new ones. It’s a bad deal for everyone now (not even YouTube’s fault - it’s the fault of the number of bots, DDOS tools, and click farms on the internet)